This invention relates to a magnetic recording and playback apparatus operative to record and play back audio signals in multiple channels and a video signal, and particularly to a magnetic recording and playback apparatus capable of recording and playing back multiple audio signals in the high-definition television signal form.
Magnetic tape recording and playback apparatuses intended for home use, i.e., rotary head, helical-scan video tape recorders (VTRs), have been designed to meet the NTSC standard television signal form (or PAL or SECAM signal form in Europe). Recently, development and commercialization of HDTV (high definition television), which is also called "high vision", for reproducing higher quality pictures have begun. High-definition VTRs are divided into the analog recording system and digital recording system, as described in an article entitled "Special issue: Annual report on television, Section 4-2, HDTV (high vision)", in the publication of The Institute of Television Engineers of Japan, Vol. 42, No. 7, pp. 655-657, published in 1988. A specific example of analog high-definition VTRs is described in the Technical Report of the above institute, ppOE56-2, pp. 7-11, published on Nov. 28 1984, and a specific example of digital high-definition VTRs is described in an article entitled "Special issue: Recent magnetic and optical recording techniques, Section 5.1, Digital VTR" in the publication of the above institute, Vol. 42, No. 4, pp. 338-346, published in 1988.
In regard to audio signals in the high-definition television, or high vision, system, commercialization is under way for the system which provides enhanced sound realism by using four channels (left channel L, right channel R, center channel C, and rear channel S), as described in the publication of the above-mentioned institute, Vol. 44, No. 3, pp. 228-233. Accordingly, it is, desirable for high-definition VTRs to have the ability for recording and playing back audio signals in four channels.
Conventionally, in the case of an analog recording high-definition VTR, analog audio signals are recorded in two channels in the longitudinal direction of the magnetic tape, while in the case of a digital recording high-definition VTR, audio signals are recorded in eight channels in the longitudinal direction of the magnetic tape.
In a NTSC-based composite digital VTR (D.sub.2 -type VTR), although this is not a high-definition VTR, digital audio signals are recorded in four channels in the rotary head scanning direction in an area different from that of the video signal track.